Semiconductor devices are frequently manufactured by performing an ion implantation process in which impurities are implanted in a wafer to change the electrical characteristics of the wafer.
FIG. 1 is a schematic diagram illustrating an example prior art apparatus for performing such an ion implantation process. The conventional apparatus of FIG. 1 includes an arc chamber 110 that ionizes the impurities and creates an ion beam B. The apparatus also includes an ion beam extracting and accelerating electrode 120 that extracts the ion beam B from the arc chamber 110 and accelerates the ion beam B. The illustrated apparatus is further provided with an end station 130 that holds a wafer W in which the impurities are implanted.
In FIG. 1, the ion beam B is created by the collision of gas molecules using electric power which is applied to the arc chamber 110. Although not shown in the figure, the ion beam extracting and accelerating electrode 120 is connected to an electric power supply for this purpose.
However, in the conventional apparatus for ion implantation, if an arc is unstably formed in the arc chamber 110, the beam current characteristics of the ion beam deteriorate. Therefore, the quality of a semiconductor device being fabricated with the beam may be problematically deteriorated, and a defect may be caused in the process.